The bacteria responsible for stomach ulcers have been linked to Parkinson's disease, according to researchers in the US. Mice infected with Helicobacter pylori went onto develop Parkinson's like symptoms. The study, presented at a meeting of the American Society for Microbiology, argues that infection could play "a significant role". The charity Parkinson's UK said the results should be treated with caution. rkinson's disease affects the brain and results in slow movements and a tremor.